This invention relates to internal combustion engines, and more particularly, to devices that preheat fuel for the carburetors of these engines.
It is well known that heating fuel prior to its introduction into the carburetor, increases the combustion efficiency of these engines. There are many obstacles to overcome when designing a fuel heating device. The object of these fuel heaters is to provide the carburetor with fuel that is warmed to a predetermined temperature. The heat output of the fuel heater must be adjustable to satisfy the varying amounts of heat necessary to heat the fuel whether the car is idling or accelerating. The heater must also work within a wide range of environmental temperatures. The heat required from the heater at warm temperatures is much less than the heat required when the outside temperature is below zero.
One of the primary problems facing current fuel heater designs is vapor lock. Vapor lock occurs when there is uneven heating of the fuel or if the fuel heater cannot adjust to a sudden increase in the demand for fuel. When this occurs, a portion of the fuel vaporizes and blocks movement of the remaining heated fuel through the fuel heater. The car is virtually useless until the vaporized fuel cools. If vapor lock occurs with any regularity, the device will not be accepted by the public.
The fuel heaters must also be inexpensive to manufacture and easy to install. The savings from this device occurs over a long period of time, and many people will not purchase it if there is a large initial investment. The prior art contains many attempts to overcome the problems faced when designing a fuel heater. In U.S. Pat. No. 4,146,002, issued to Quinn, on Mar. 27, 1979, the fuel is heated by passing it through a helically shaped tubing that is surrounded by engine coolant. My prior invention U.S. Pat. No. 4,367,717, issued Jan. 11, 1983, also utilizes engine coolant to heat the fuel. In my invention, the fuel is passed through a heat exchanger which heats and regulates the fuel temperature as it passes into the carburetor. My invention, as well as many others, has numerous machine parts and is expensive to manufacture.
The prior art has demonstrated that the use of fuel heaters increases fuel economy and decreases the amount of unburned fuel released into the environment. The prior fuel heaters have not provided the public with a reliable, inexpensive fuel heater. It is accordingly clear that a need remains in the art for a fuel heater that will overcome the disadvantages of the current fuel heaters.